Pressure-regulating mechanism for wood-grinding machines



F. A. PESCHL Filed July 18 '1923 I ZY/Ue To/Oi' f 2 j/iaby June 17' 1924.

PRESSURE REGULATING macrmmsm FOR woon GRINDING MACHINES 1 m i M Q ROM 9 L J. .4: 2 Km 6 =lll. 5 V a m v. 6 fl J gv A w 9 1PM 2 7 o fa June 17,1924. ,497,870

F. A. PESCHL PRESSURE REGULATING mscr-mmsm FOR WOOD GRINDING MACHINES Filed July 18. 1923 2 shee'tsrshet z CAD Patented June 17, 1924.

a UNITEn STATES 1,497,870 PATENT OFFICE,

FRANK A. PESCHL, or BERN, SWITZERLAND, ASSIGNOR TO INTERNATIONAL PAPER COMPANY, A CORPORATION OF NEW YORK.

PRESSURE-REGULATING MECHANISM FOR WOODGRINDING"MACHINES.

Application filed July 18 1923. Serial No. 652,287.

To all whom it may concern:

Be it known that I, FRANK A. PESCI-IL, a citizen of the Republic of Switzerland (having taken out his first papers to become a citizen of the United States), residing at Bern, Switzerland, have invented certain new and useful Improvements in Pressure- Regulating Mechanism for Wood-Grinding Machines, of which the following is a specification, reference being had therein tc the accompanying drawings. a

This invention relates to mechanism for grinding wood for theproduction of wood pulp for use more particularly in the manu facture of paper. Machines for this "purpose comprise usuallv a rotary grindstone, against the periphery of which, wood held in a pocket. is forced by a pressure device carried by a piston working in a power cylinder supplied with actuating pressure fluid. lVhen a number of grindstones, with their associated pressure devices, are employed, with the grindstones driven from a common source of power, it is the practice to supply the actuating pressure-fluid from a common source, so that the pressure devices for the stones will operate'under the same pressure, and with the stones of equal diameter rotating at the same speed, the wood will be disintegrated in a uniform manner, and a uniform quality and grade of pulp will be produced. It is found however in the operation of a number of'stones, that they will frequently wear unequally, and due to such unequal wear, the diameter of one stone willbecome less than that of another, and the peripheral speeds of the stones will consequently vary, and with the pressure devices acting on the stones at the same pressure, the disintegratingaction of the stones on the wood will vary, and the wood pulp produced will not be uniform but will vary as to grade and quality.

It is the aim of the present invention to, overcome thisnon-uniformity of the grand;

ing action. and the invention consists of means for controlling the flow of the pressure-fluid from a common source of supply to the pressure devices of two grindstones, which means are connected together for joint operation, and are adapted to be set or regulated to vary theratio of pressures acting on the pressure devices; whereby in the event of the'diameter of one stone becoming less than that of the other, with the peripheral speed of the smallerstone correspondingly less than that. ofv the larger stone, the pressureacting on the two pres sure devices may be variedproportionately to the variation in the peripheral. speeds, and the proper ratio ofpressures may be established to bring about a uniformity in the reducing action of the two stones on the wood- I In its more specific embodiment the invention consists in providing in the pipes 0 connections between the source of pressure fluid and the pressure devices of the two stones, controlling or reducing valves operated by the pressure-fluid and connected together for joint action, and adapted. to be set or regulated to vary the ratio of pressures acting on the pressure devices.

In the accompanying drawings:

Fig. l is an elevation partly in section of my improved controlling mechanism. I F 2 is. a view in elevationshowing the same applied. to control the pressure devices of two grinding vmachines.

Referring to the drawings:

Referring more particularlyto- Fig. 2, l and 2 designate two wood grinding machines, comprising each as usual, 2. suitable frame or housing in which is mounted a rotary grindstoneB, said stones being driven from a common source of power andthe housings sustaining a number of pockets 4 for holding the wood to be ground. In the pockets 4, pressure devices or shoes 5 are arranged to act on the wood andforce the same against the peripheries of the grindstones, which shoes are connected with the, inner ends of plston rods 6 which are in turn connected to pistons 7 sliding in power cylinders 8 sn ported at the outer ends of the pockets. 5n the admission of pressure fluid, usually water, to the upper ends of the cylinders, the pistons will be advanced and the pressure shoes will act to force the wood against the grindstones, and on the admission of pressure-fluid to the opposite ends of the cylinders, the pistons will be retracted and the pressure shoes backed off or moved away from the stones to permit the pockets to be refilled. The foregoing'parts may be of the usual and'ordina-ry construc-f tion well known in this art, and in so far as the application of my invention is concerned, the grinding machines above described may have each a plurality of Woody holding pockets as shown and as is now the common practice, or each stone may be equipped with but a single pocket. as desired.

The actuating pressure-fluid for the pressure devices of the two grinding machines flows front a common source of supply through a pipe 10, from which pipes 11 and 12 branch and lead respectively to the two grinding machines, where they are connected by suitable pipes 13 to the several pow-er cylinders; I

In accordance with my invention, the branch pipe 11 has connected in it a valve casing 14 which divides the pipe into an upper pressure-fluid receiving portion 11 and a lower pressure-fluid delivery portion 11 which portions communicate with each other through valve ports 16, 16 formed in the lower end of the portion 11*, which extends within and is spaced from the walls of the valve casing. The ports 16, 16 are arranged in horizontal alignment with each other and are surrounded by valve seats with which cooperate two valve heads 17, 17 on the inner end of a horizontal valve stem 18. The valve casing extends horizontally outwardly at its outer side in the form of? a horizontal cylinder 19 which communicates at its inner end with the interior of the valve casing, and is closed at its outer end by a cap 20; and an actuating piston 21 slides and isfiXed to the outer end of the valve stem. At its outer side the piston is pivoted as at 22 to the inner end of a rod 23 which slides through the cap 20 and has its outer end pivoted to an upright lever 24 pivotally mounted at its upper end on an arm 25 fixed to and projecting upwardly from the cylinder, the purpose of which lever will presently appear. The valve heads, in connec tion with the valve seats and piston, constitute a reducing valve mechanism controlled by the pressure of the pressure-fluid after flowing through the ports 16, 16, in other words by the secondary or reduced pressure, and in the movements of the valve heads by the piston under the pressure oi? the fluid acting in the cylinder, the flow of the pressure-fluid through pipe 11 will be controlled, as will be more fully described hereinafter.

The branch pipe 12 is also provided with a reducing valve mechanism similar to that just described, avalve casing 26 being Vapplied 1n the pipe and dividing the same into an upper pressurefiuid receiving portion 12% and a lower pressure-fluid delivery por tion 12 communicating with each other through valve ports 27, 27 formed in the lower end of the portion 12. The ports are controlled by valve heads 28, 28 on a horizontal valve stem 29 connected with an actuating piston 30 sliding in a cylinder 31 communicating with the interior of the valve casing. The piston is pivoted to a rod 32 sliding through the cylinder cap, which rod is pivoted at its outer end to an upright lever 33 pivotally mounted at its upper end to an arm 34- fixed to the cylinder.

The two levers 2 1 and 33 are similar in length, and are pivoted to the rods 23 and 32 at the same distance from the axes of the pivotal mountings of the ends of the levers, and these levers are connected together at their lower ends by a link 36 adjustable in length by a turn buckle 36 whichcauses the two sets of valves to act co-jointly with each other in the movements of said valves under the influence of the pressure-fluid in the branch pipes; and means are provided whereby the points of connection of the link with the two levers may be adjusted to and from the axes of the pivotal mountings of the upper ends of the levers, so that the leverage of one set of valves on the other may be varied to vary the ratios of pressure on the pressure devices of the two grinding machines, In the present instance this is effected by forming in the lower portion of lever 24, an arcuate slot 37, and a similar slot 38 in the lever 33, in which slots clamp screws 39 and 40 carried by the ends of the link, respectively engage. The form, size and relative arrangement of the several parts above described are such that when the link 36 is set in the position shown in full lines in 1 with its ends at the lower ends of the arcuate slots, the two sets of valves will be in the same positions relative to their respective valve seats, and the flow of the pressure-fluid from the common source of supply through the branch. pipes to the actuating devices of the two grinding machines will be equal, and the pressure devices will act with the same degree of pressure in forcing the wood against the stones, the valves in this position of the parts being half open and allowing equal flow of the pressure-fluid in the two branch pipes. If it be assumed however, that, on account of the unequal wear on the two grindstones, a variation in diameter occurs and a consequent variation of peripheral speeds, and a pressure ratio of 1 to 2 for instance is desired. the higher pressure delivered by pipe 12 and the lower pressure delivered by pipe 11, the end of the link 36 is shifted along the arcuate slot 37 in lever 24 and. is set in the position shown by dotted lines in Fig. 1 at a point midway between the ends of the lever. The forces on the pistons 21 and 30 will in the first instant after the adjustment of the link, be equal, but due to the fact that the effective leverage on piston 21 will be less than that on piston 30, the lever sys tem will move towards the left in Fig. 1, and the valve heads17, 17 will throttle the flow of the fluid in branch pipe 11, and consequently the pressure will decrease until the ltltl therefore cease its movement towards the left, and will now move towards the right. The valves 17, 17 will thus permit greater flow, and the pressure on piston 21 will increase andwill have the effect of moving the lever system again towards the left. These movements to the right and left will be repeated until a position of theparts,

and the two sets of valves, will be established which will allow for the proper. ratio of flow through the branch pipes, and .conse quently the proper ratio of pressures acting on the pressure devices of the two grinding machines.

It will be understood of course that other ratios of pressure than that just described may be established by setting the link 36 at intermediate positions on the levers; and it will be understood also if a higher pressure is to be delivered by pipe 11 theend of the link would be adjusted along the slot 38 in lever 33.

Having thus described my invention, what I claim is:

1. I11 a wood grinding mechanism, the combination of a plurality of rotary grindstones, a pressure device associated with each stone for forcing the wood against the same, said pressure devices being connected with a common source of pressure-fluid for operating the same, and means associated with the respective pressur devices and governed by the pressure of the pressurefiuid for controllin the pressure on the pressure devices, said means being intercon nected for joint operation, and adapted to be set to vary the ratio of pressures of the pressure-fluid acting on the pressure devices.

2. In a wood grinding mechanism, the combination of a plurality of grindstones, a pressure device associated with each stone for forcing the wood against the stone, pipes leading from a common source of pressurefiuid to the respective pressure devices to actuate the same, and means controlled by th pressure of the pressurefiuid in said pipes for varying the ratio of pressures of the pressure fluid acting on the pressure devices.

3. In a wood grinding mechanism, the combination of a plurality of grindstones, a pressure device associated with each stone for forcing the wood against the stone, pipes leading from a common source of pressureiiuid to the respective pressure devices to actuate the same, and means controlled by the pressure of the pressure-fluid in said pipes, and adapted to be adjusted to vary.

the ratio of pressures of the pressure fluid acting on the pressure crevices.

4. In a wood grinding machine, the combination of a plurality of rotary grindstones, a pressure device associated with eachstone for forcing the wood against the same, pipes leading from a common source of pressure-fluid to the respective pressure devices, controlling valvesin said pipes, operated by the pressure of the pressure-fluid therelnand operative connect ons between I said valves.

5. In a wood grinding machine, the com bination of a plurality of rotary grindstones, a pressure device associated with each stone for forcing the wood against the same, pipes leading from a common source of pressure-fluid to the respective pressure devices, controlling valves in said pipes, operated by the pressure of the pressure-fluid therein, operative connectionsbetween said valves, and means for adjusting said connections to vary the ratio of pressures of th pressure-fluid acting on the pressure devices. b

6. In a wood grinding machine, the combinaiton of a plurality of rotary grind stones, a pressure device associated with each stone to force the wood against the stone, a source of pressure-fluid, connections between said source and the ressure devices for supplying pressure-fluiil thereto, and means in said connections and governed by the pressure of the pressure-fluid for; controlling the flow of the same therethrough, said means being interconnected for joint operation, and being relatively adjustable to vary the ratio of pressures of the pressure-fluid.

acting on the pressure devices.

7. In a wood grindlng mechanism, the

combination of a plurality of rotary grindstones, a pressure device associated with each stone to force the wood against the same, a source of pressure-fluid, connections between said. source and the pressure devices for supplying pressure-fluid thereto, and means in said connections actuated by the pressure of the pressure-fluid for controlling the flow of thesame, said means being interconnected for joint operation, and being relatively adjustable to vary the ratio of pressures of the pressure-fluid acting on the pressure devices.

8. In a wood grinding mechanism, the combination of a plurality of rotary grindstones, a pressure device associated with each stone to force the wood against the same. pipes leading from a common source of pressuredluid to the respective pressure devices, and pressure reducing valves in said pipes operated by the pressure-fluid therein and adjustably connected together for joint operation; whereby by adjusting said valves relatively to each other, the ratio of pressures of the pressure-fluid acting On the pressure devices may be varied.

9. In a wood grinding mechanism, the combination of a plurality of rotary grindstones, a pressure device associated with each stone for forcing the Wood against the same, pipes leading from a common source of pressure-fluid to the respective pressure devices to actuate the same, pressure reducing valves in said pipes operated by the pressure-fluid therein, pivotally mounted levers connected with said valves, a link connecting said levers together for joint operation, and means for adjusting the points of connection of the link and levers to and from the axis of the levers. o

10. In a Wood grinding mechanism, the combination of a plurality of rotary grindstones, a pressure device associated With each stone for forcing the Wood against the same, pipes leading from a common source of pressure-fluid to the respective pressure devices to actuate the same, pressure reducing valves in said pipes operated by the pressure-fluid therein, pivotally mounted levers connected to said valves, and a link connecting said levers together for joint operation, and adjustable relatively thereto to and from the axis of the levers, said link being adjustable in length.

11. In a Wood grinding mechanism, the combination of a plurality of rotary grindstones, a pressure device associated With each stone for forcing the Wood against the same, pipes leading from a common source of pressure-fluid to the respective pressure devices to actuate the same, valves in said pipes for controlling the flow of the pressure-fluid therethrough, actuating pistons for said'valves operated by the pressure-fluid in said pipes, and a lever connection between said pistons adapted to be set to vary the leverage of one actuating piston onthe other, and thereby vary the ratio of pressures acting on the pressure devices. l

12. In a WOOEI grinding mechanism, the combination of a plurality of rotary grindstones, a pressure device associated} with each stone for forcing the Wood against the same, pipes leading from a common source of pressure-fluid to the respective pressure devices to actuate the same, valves in said pipes for controlling the flow of the pressure-fluid therethrough, actuating pistons for said valves operated by the pressure of the pressure-fluid therein, said pistons being connected together for joint operation, and means for changing the action of the pistons on each other to vary the ratio" of pressures of the pressure-fluid acting on the pressure devices.

13.. In a Wood grinding mechanism, the combination of a plurality of rotary grindstones, a pressure device associated With each stone for forcing the Wood against the same, pipes leading from a common source of pressure-fluid to the respective pressure devices to actuate the same, valves in said pipes for controlling the flow of the pressure-fluid therethrough, actuating, members for said valves operated by the secondary pressure of the pressure-fluid, and connections between said actuating members adapted to be set to vary the ratio of pressures of the pressure-fluid acting on the pressure devices.

In testimony whereof, I have affixed my signature hereto.

FRANK A. I PESGHL. 

